In a conventional vehicle power unit including an internal combustion engine with an electric power generator and a lubricant oil filter attached to the body of the engine, the oil filter is disposed outwardly of the outer periphery of the electric power generator that is mounted on the crankshaft (see Patent Document 1).
Such a vehicle power unit has a problem in that it tends to be large in size because its crankcase is enlarged outwardly by the lubricant oil filter protruding outwardly of the outer periphery of the electric power generator.